Switched-mode power converters typically comprise a power converter network comprising one or more power switches and a controller configured to control the one or more power switches. In particular, the controller may be configured to control the time instances at which the one or more power switches are put into an on-state and into an off-state. The controller may comprise one or more sensing pins configured to receive various measurement signals from the power converter network. The controller may use the measurement signals to control the one or more power switches. In typical implementations of power converters, several different sensing pins are used for several different measurement signals. By way of example, a typical approach is to use several different pins for current sensing and voltage measurements, respectively.
Power converters, e.g. power converters which are used in retrofit lamp driver circuits, are strongly constrained in cost, size and component count. As a consequence, integrated circuits (ICs) used in such power converters (e.g. as controllers) should be designed with a minimum number of pins. Minimizing the pin count typically reduces the number of external components, the losses in sensor elements (voltage dividers, shunts) and the chip area required for additional pads and analog sensing blocks. Hence, the pin count is an important cost driver for low cost power converters.
In the present document, power converters are described which allow the sensing of multiple measurement signals using a single sensing pin. By way of example, a flyback power converter with one pin sensing (for system detection, current measurement, bus voltage measurement and/or avalanche measurement) is described. Furthermore, a power factor correction (PFC) with a multi-function pin for simultaneous detection of the input voltage, the bus voltage and/or for zero-crossing timing measurement is described.